Creating Custom Protocol (Windows 7)

I've been trying to create a custom protocol (open_php_file://) to open local files through the browser. I've created the following registery-keys:

HKEY_CLASSES_ROOT
     open_php_file
          (Default) = "URL:PHPEd protocol"
          URL Protocol = ""
          DefaultIcon
               (Default) = "phped.exe"
          shell
               open
                    command
                         (Default) = "C:\Program Files (x86)\NuSphere\7.0\phped.exe" "%1"

The problem is: I can't open files in my browser (example: open_php_file://c:\file.txt), and the protocol isn't listed in the windows default programms.